Chemodiversity of Cirsium fruits: Antiproliferative lignans, neolignans and sesquineolignans as chemotaxonomic markers

Sesquilignans: Current research and potential prospective

Lignans are widely distributed in nature, primarily found in the xylem and resins of plants, with the constituent units C6-C3, and their dimers are the most common in plants. In recent years, the trimeric sesquilignans have also received increasing attention from scholars. More than 200 derivatives have been isolated and identified from nearly 50 families, most of which are different types (monoepoxy lignans, bisepoxy lignans, benzofuran lignans) connected with simple phenylpropanoids through ether bonds, C-C bonds, and oxygen-containing rings to constitute sesquilignans. Some of them also possess pharmacological properties, including antioxidants, hepatoprotectives, antitumors, anti-inflammatory properties, and other properties. In addition, the chemical structure of sesquilignans is closely related to the pharmacological activity, and chemical modification of methoxylation enhances the pharmacological activity. In contrast, phenolic hydroxyl and hydroxyl glycosides reduce the pharmacological activity. Therefore, the present review aims to summarize the chemical diversity, bioactivities, and constitutive relationships to provide a theoretical basis for the more profound development and utilization of sesquilignans.

Machine-Learning- and Structure-Based Virtual Screening for Selecting Cinnamic Acid Derivatives as Leishmania major DHFR-TS Inhibitors

The critical enzyme dihydrofolate reductase-thymidylate synthase in Leishmania major (LmDHFR-TS) serves a dual-purpose role and is essential for DNA synthesis, a cornerstone of the parasite's reproductive processes. Consequently, the development of inhibitors against LmDHFR-TS is crucial for the creation of novel anti-Leishmania chemotherapies. In this study, we employed an in-house database containing 314 secondary metabolites derived from cinnamic acid that occurred in the Asteraceae family. We conducted a combined ligand/structure-based virtual screening to identify potential inhibitors against LmDHFR-TS. Through consensus analysis of both approaches, we identified three compounds, i.e., lithospermic acid (237), diarctigenin (306), and isolappaol A (308), that exhibited a high probability of being inhibitors according to both approaches and were consequently classified as promising hits. Subsequently, we expanded the binding mode examination of these compounds within the active site of the test enzyme through molecular dynamics simulations, revealing a high degree of structural stability and minimal fluctuations in its tertiary structure. The in silico predictions were then validated through in vitro assays to examine the inhibitory capacity of the top-ranked naturally occurring compounds against LmDHFR-TS recombinant protein. The test compounds effectively inhibited the enzyme with IC50 values ranging from 6.1 to 10.1 μM. In contrast, other common cinnamic acid derivatives (i.e., flavonoid glycosides) from the Asteraceae family, such as hesperidin, isovitexin 4'-O-glucoside, and rutin, exhibited low activity against this target. The selective index (SI) for all tested compounds was determined using HsDHFR with moderate inhibitory effect. Among these hits, lignans 306 and 308 demonstrated the highest selectivity, displaying superior SI values compared to methotrexate, the reference inhibitor of DHFR-TS. Therefore, continued research into the anti-leishmanial potential of these C6C3-hybrid butyrolactone lignans may offer a brighter outlook for combating this neglected tropical disease.

Arylnaphthalene Lignans with Anti-SARS-CoV-2 and Antiproliferative Activities from the Underground Organs of Linum austriacum and Linum perenne

Diphyllin (1) and justicidin B (2) are arylnaphthalene lignans with antiviral and antiproliferative effects. Compound 1 is also known as an effective inhibitor of the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). To evaluate the in vitro antiviral and cytotoxic potency of both lignans in SARS-CoV-2 -infected cells and various cancer cell lines, respectively, 1 and 2 were isolated from the underground organs of Linum austriacum and Linum perenne. Two previously undescribed arylnaphthalene lignans, denominated linadiacin A and B (3 and 4), were also isolated and identified. In acidic media, 3 was converted by a two-step reaction into 2 via the intermediate 4. Optimum acid treatment conditions were determined to isolate lignans by one-step preparative high-performance liquid chromatography (HPLC). The results of the conversion, HPLC-tandem mass spectrometry, nuclear magnetic resonance spectroscopy, and molecular modeling studies allowed complete structure analysis. Compounds 1 and 2 were the most effective against SARS-CoV-2 with a 3-log reduction in the viral copy number at a 12.5 μM concentration. Ten human cancer cell lines showed sensitivity to at least one of the isolated lignans.

Botany, traditional uses, phytochemistry and pharmacological activity of Crataegus pinnatifida (Chinese hawthorn): a review

OBJECTIVES

Crataegus pinnatifida (C. pinnatifida), including C. pinnatifida Bge. and its variant C. pinnatifida Bge. var. major N, E. Br., has traditionally been used as a homologous plant for traditional medicine and food in ethnic medical systems in China. Crataegus pinnatifida, especially its fruit, has been used for more than 2000 years to treat indigestion, stagnation of meat, hyperlipidemia, blood stasis, heart tingling, sores, etc. This review aimed to provide a systematic summary on the botany, traditional uses, phytochemistry, pharmacology and clinical applications of C. pinnatifida.

KEY FINDINGS

This plant contains flavonoids, phenylpropanoids, terpenoids, organic acids, saccharides and essential oils. Experimental studies showed that it has hypolipidemic, antimyocardial, anti-ischemia, antithrombotic, anti-atherosclerotic, anti-inflammatory, antineoplastic neuroprotective activity, etc. Importantly, it has good effects in treating diseases of the digestive system and cardiovascular and cerebrovascular systems.

SUMMARY

There is convincing evidence from both in vitro and in vivo studies supporting the traditional uses of C. pinnatifida. However, multitarget network pharmacology and molecular docking technology should be used to study the interaction between the active ingredients and targets of C. pinnatifida. Furthermore, exploring the synergy of C. pinnatifida with other Chinese medicines to provide new understanding of complex diseases may be a promising strategy.

Antioxidant Effects and Phytochemical Properties of Seven Taiwanese Cirsium Species Extracts

In the present investigation, we compared the radical-scavenging activities and phenolic contents of seven Taiwanese Cirsium species with a spectrophotometric method. We further analyzed their phytochemical profiles with high-performance liquid chromatography–photodiode array detection (HPLC–DAD). We found that the flower part of Cirsium japonicum var. australe (CJF) showed the best radical-scavenging activities against 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), and the hypochlorite ion, for which the equivalents were 6.44 ± 0.17 mg catechin/g, 54.85 ± 0.66 mmol Trolox/g and 418.69 ± 10.52 mmol Trolox/g respectively. CJF also had the highest contents of total phenolics (5.23 ± 0.20 mg catechin/g) and phenylpropanoids (29.73 ± 0.72 mg verbascoside/g). According to the Pearson’s correlation coefficient, there was a positive correlation between the total phenylpropanoid content and ABTS radical-scavenging activities (r = 0.979). The radical-scavenging activities of the phenylpropanoids are closely related to their reducing power (r = 0.986). HPLC chromatograms obtained in validated HPLC conditions confirm that they have different phytochemical profiles by which they can be distinguished. Only CJF contained silicristin (0.66 ± 0.03 mg/g) and silydianin (9.13 ± 0.30 mg/g). CJF contained the highest contents of apigenin (5.56 ± 0.09 mg/g) and diosmetin (2.82 ± 0.10 mg/g). Among the major constituents, silicristin had the best radical-scavenging activities against DPPH (71.68 ± 0.66 mg catechin/g) and ABTS (3.01 ± 0.01 mmol Trolox/g). However, diosmetin had the best reducing power and radical-scavenging activity against the hypochlorite anion (41.57 ± 1.14 mg mmol Trolox/g). Finally, we found that flavonolignans (especial silicristin and silydianin) and diosmetin acted synergistically in scavenging radicals.

Naturally Lignan-Rich Foods: A Dietary Tool for Health Promotion?

Dietary guidelines universally advise adherence to plant-based diets. Plant-based foods confer considerable health benefits, partly attributable to their abundant micronutrient (e.g., polyphenol) content. Interest in polyphenols is largely focused on the contribution of their antioxidant activity to the prevention of various disorders, including cardiovascular disease and cancer. Polyphenols are classified into groups, such as stilbenes, flavonoids, phenolic acids, lignans and others. Lignans, which possess a steroid-like chemical structure and are defined as phytoestrogens, are of particular interest to researchers. Traditionally, health benefits attributed to lignans have included a lowered risk of heart disease, menopausal symptoms, osteoporosis and breast cancer. However, the intake of naturally lignan-rich foods varies with the type of diet. Consequently, based on the latest humans' findings and gathered information on lignan-rich foods collected from Phenol Explorer database this review focuses on the potential health benefits attributable to the consumption of different diets containing naturally lignan-rich foods. Current evidence highlight the bioactive properties of lignans as human health-promoting molecules. Thus, dietary intake of lignan-rich foods could be a useful way to bolster the prevention of chronic illness, such as certain types of cancers and cardiovascular disease.